Calaamadaha indhaha waxa loo rogaa calaamadda hadda jirta iyada oo la gelinayo fiber-ka indhaha.Module-ka Si PIN waxa uu la socdaa wareegga hore-u-kordhinta kaas oo awood u siinaya signalka daciifka ah ee hadda jira in la kordhiyo oo loo beddelo signalka danabka si loo gaadho habka beddelka ee kor u qaadida calaamadaha sawir-qaadista.